Base for an electron tube having retention provisions therein

ABSTRACT

A protective base for an electron tube having a plurality of substantially rigid connective leads arranged in spaced relationship to protrude from the tube closure surface. The tube base has a plurality of perforations arrayed therein to accommodate the protrusion of the respective connective leads therethrough. At least two substantially oppositely disposed perforations in the array are formed to have at least two diverse dimensions, one dimension of which is smaller than the diameter of the respective lead protruding therethrough, to provide predetermined spaced apart regions of pressured contact and regions of noncontact with said lead to effect a retention relationship between the base and the respective connective lead accommodated therein.

United States Patent [72] Inventor Doyle Alfred Wood Primary ExaminerRichard E. Moore Ottawa, Ohio AttorneysNorman J. OMalley, Donald R. Castle and [21] Appl. No. 843,441

Frederick H. Rinn {22] Filed July 22, 1969 [45] Patented Mar. 9, 1971 [73] Assignee Sylvania Electric Products Inc.

ABSTRACT: A protective base for an electron tube having a plurality of substantially rigid connective leads arranged in [5 4] BASE FOR-AN ELECTRON TUBE HAVING spaced relationship to protrude from the tube closure surface. The tube base has a plurality of perforations arrayed therein to accommodate the protrusion of the re leads therethrough. At least two sub WWW;

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INVENTOR. DOYLE A. WOOD ATTORNEY BASE FOR AN ELECTRON TUBE HAVING RETENTION PROVISIONS TI'IEREIN BACKGROUND OF THE INVENTION This invention relates to electron tubes and more particularly to a protective base for an electron tube wherein the base has discrete perforation means for effecting retention to the tube.

Many types of electron tubes, especially those wherein the sealed exhaust tubulation and an array of substantially rigid connective leads protrude from the tube stem closure surface, utilize protective bases conventionally formed of plastic insulative material. These are commonly fabricated to provide an enclosure for the tubulation and an array of perforations to accommodate protrusion of the leads therethrough. Such construction effects protection for the sealed tubulation and the glass seals of the connective leads and provides strength to the protruding connective leads during insertion and removal from compatible electrical socket means. Additionally, the base usually incorporates an alignment provision in the tubulation protection portion to facilitate proper insertion of the respective leads into the tube socket.

To achieve the intended advantages, it is essential that the protective base be securely attached to the tube in a manner to withstand the conventional usage of tube-socket insertion and withdrawal One common way of attaching the base to the tube is by use of plastic cement applied between the base and the glass around the stem leads. This method is economically disadvantageous as the extra production operation requires material, labor, equipment and time. Another known attachment procedure utilizes a plurality of annular base perforations having diameters smaller than the diameters of the substantially rigid tube leads protruded therethrough. For example when a tube lead of a diameter such as 0.040 inches is inserted through an annular base perforation having a diameter of say 0.037 inches, it has often been found necessary to preheat the plastic base before it is forced over the stem leads to allow the plastic to conform to the lead. The undersize annular holes have adverse effects in that, without the application of heat, the pins are prone to bend because of the extreme force required to insert them through the smaller openings. Furthermore, the radial compression circumferentially exerted by the lead tends to rupture the plastic which relieves the pressure of retention. In addition, the undersize holes allow for no radial displacement of the respective leads which aggravates lead bending if the particular leads are slightly misaligned.

OBJECTS AND SUMMARY OF THE INVENTION It is an object of the invention to reduce the aforementioned disadvantages and to provide electron tube base retention means that enables facile adherence of the base to the tube. Another object is to effect base adherence in a manner to reduce the prevalence of bent leads. A further object is to provide means for base adherence that accommodates some misalignment of the retention leads.

The foregoing objects are achieved in one aspect of the invention by utilizing a protective base having therein an array of perforations matching the array of connective leads protruding therefrom. At least two of the perforations in the base, which are substantially distally positioned from one another in the array, are formed as diverse-dimensioned retention'perforations. A first or length dimension thereof is greater than the diameter of the lead protruding therethrough and a second or breadth dimension thereof is smaller than the respective lead diameter. Such dimensioning of the respective perforations provides predetermined spaced apart regions of pressured contact and regions of noncontact between the surrounding base material and the lead. Thus, there is effected a discrete retention relationship between certain perforations of the base and the respective tube connective leads wherein the regions of contact and noncontact have transition zones therebetween to provide pressure relief of the insulative base material adjacent thereto.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of the base member illustrating one orientation embodiment and one shape embodiment of the diverse-dimensioned perforations therein;

FIG. 2 is a sectional view of the base member as shown in FIG. I, taken along the line 2-2 thereof, illustrating base positioning on a tube structure; and

FIGS. 3 and 4 are plan views of two embodiments of the retention perforations fonned in the base member.

DESCRIPTION OF THE PREFERRED EMBODIMENT For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following specification and appended claims in connection with the aforedescribed drawings.

With reference to FIGS. 1 and 2, there is shown a protective base member 11 for an electron tube 13, which is phantomed in FIG. 2 to illustrate the adhering relationship therebetween. The base 11 is of an electrical insulative material, such as a polyarnide plastic, for example nylon. Formed in a rimlike portion 14 thereof are a plurality of substantially circular perforations l5 and at least two diverse-dimensioned retention perforations 17. These are spaced to match the array of a plurality of substantially rigid round rodlike connective leads 19, two of which are shown in FIG. 2, arranged in spaced relationship to protrude from a substantially planar portion of the tube stem closure surface 21 surrounding a sealed tubulation 23 projecting outwardly therefrom along substantially the longitudinal tube axis 25. When the base 11 is positioned or seated in the closure surface 21 of the tube 13, the base axis 25 substantially coincides with the longitudinal tube axis 25.

In greater detail, the base member 11 is formed with the rimlike portion 14 surrounding an axially oriented hollow stack portion 29 fashioned to protectively encompass the sealed tubulation 23. Exteriorly formed on the stack portion 29 is a raised longitudinal rib or lug 31 which mates with a compatible slot in a socket member, not shown, to insure proper orientation of the connective leads in the respective socket receiving means. As shown, the tube lead arrangement and the matching base perforation array are respectively disposed in a substantially circumferential manner in spaced relationship to the tube and base axes 25 and 25 respectively. It is evident that the leads and matching perforations could be arranged in other arrays, such as ovoid or rectangular, and still be in keeping with the concept.

With reference to FIGS. 1, 2, and 3, there are at least two diverse-dimensioned retention perforations 17 which are substantially distally positioned from one another in the array. Each of these retention perforations 17 has a primary axis of symmetry 35 and a first or length dimension a which is greater than the diameter x of the tube connective lead 19 protruding therethrough. The length dimension a substantially coincides with the perforation primary axis of symmetry 35. The retention perforation 17 also has a second or breadth dimension b that is smaller than the diameter x of the respective lead 19. In the shown embodiment, the diverse-dimensioned retention perforations 17 are oriented in a manner that their primary axes of symmetry 35 are substantially radially disposed in relationship to the base axis 25. In FIG. 3, the lead I9 is phantomed with reference to the undeforrned perforation 17 to indicate the regions of contact and noncontact between the material defining the perforation 17 and the lead 19. The dimensioning of the retention perforation 17 provides predetermined spaced apart regions of noncontact 37 and 38 and regions of pressured contact 39 and 40 between the surrounding base material 12 and the respective leads 19 to effect a retention relationship between the base member 11 and the tube 13. In this embodiment, the substantially circular perforations 15 have diameters a larger than the diameters x of the rodlike connective leads 19 associated therewith. The length dimension a of the respective retention perforations 17 substantially equals the diameters a of the circular perforations 15.

The embodiment of the retention perforation 17 as shown in FIGS. 2 and 3 illustrates a substantially elongated or slotshaped opening defined by a pair of side portions 41 and 42 and a pair of end portions 43 and 44. Bisectors 45 and 47 of the side portions 41 and 42 and of the end portions 43 and 44 meet at a common point of intersection on the axis of symmetry 35 which point is equidistant between the members of the side and end portions 41, 42 and 43, 44 respectively. The second or breadth dimension b is defined through the point of intersection 0 being normal to the perforation axis of symmetry 35.

There are gradual transition zones 49, 50, 51, and 52 between the regions of contact 39 and regions of noncontact 37 to provide for pressure relief of the insulative base material adjacent thereto. Thus, these elongated or slotlike perforations 17 provide sufficient noncontact area 37 to allow for a certain amount of lateral movement of the plastic material in the aforementioned transition areas as the perforation 17 is deformed during insertion of the lead 19. In addition to the vectors of radial compression 55, there are lateral vectors of compression 57 which in moving substantially toward the respective transition zones 49 to 52 tend to gradually relieve some of the pressure exerted against the base material by the lead 19. This gradual relief at the transition zones reduces the tendency of plastic rupture and enhances the retention characteristics inherent in the perforation-lead contact. The limited and discrete contact between the side portions 41, 42 of the slot and the lead 19 allows for facile insertion of the leads therein and provides adequate retention of the base 11 on the leads 19; this in turn effects desired adherence of the base 11 to the tube 13. Because of the limited and discrete type of contact between the base perforation 17 and the lead 19, a reduced amount of force is utilized in applying the base 11 to the tube 13. Consequently, the bending of leads 19 during base-to-tube application is greatly diminshed. Since the length dimension a of the retention perforation 17 is greater than the diameter x of the lead 19 there is accommodation for some radial misalignment of the retention leads 19. As shown, the points of intersection o of the retention perforations 17 are located on the centerline of the lead circle 61.

Another embodiment of the diverse-dimensioned perforation is shown in FIG. 4 in the form of a substantially equilateral triangle shaped opening 17' being defined by three substantially equal side portions 64, 65, 66 and having a primary axis of symmetry 35. Again, the lead 19 is phantomed with reference to the undeformed perforation 17' to indicate the regions of contact and noncontact between the material deforming the perforation 17 and the lead 19. The bisectors 67, 68, 69 of the three substantially equal side portions 64, 65, 66 meet at a common point of intersection 0 on the axis of symmetry 35' which point is equidistant between the respective sides 64, 65, 66. In this embodiment 17, there are three regions of noncontact 71, 72, 73, defined by the apices of the triangle, and three regions of pressured contact 75, 76, 77 between the surrounding base material 12 and the respective leads 19, defined by the respective sides, to effect the retention relationship. The length dimension d of the triangular perforation 17' is defined by the height of the triangle. The breadth dimension e is defined through the point of intersection 0 [being normal to the perforation axis of symmetry 35'. The points of intersection 0 of the triangular perforation 17 are located in the centerline of the lead circle 61. As in the first embodiment, there are vectors of radial compression 55 and lateral vectors of compression 57. These lateral vectors 57 move substantially toward the respective transition zones 79- 84 and tend to gradually relieve some of the pressure exerted against the base material by the lead 19, the advantages of which have been described in relation to the first embodiment.

, While orientation of the diverse-dimensioned retention perforation 17 is shown with the axis of symmetry 35 being radially oriented relative to the axis 25' of the base 11, the concept is not limited solely to such positioning. With the point of intersection 0 being located on the centerline 61 of the lead array, the axis of symmetry 35 of the retention perforation 17 may be rotationally positioned thereabout.

While two distally oriented retention perforations are shown and described for the considered base embodiments, three or more can be used if considered desirable.

Thus, there is provided an electron tube base retention means that accomplishes facile adherence of the base to the tube without the need of heat or cement. The prevalence of bent leads is reduced, and a degree of lead misalignment is accommodated by the described embodiments of the improved retention perforations.

While there have been shown and described what are at present considered the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention as defined by the appended claims.

lclaim:

1. An improvement in a protective base for an electron tube having a longitudinal axis therethrough and a plurality of substantially rigid substantially round rodlike connective leads ar ranged in spaced relationship to protrude from a substantially planar portion of the tube stem closure surface surrounding a sealed tubulation projecting substantially as axially therefrom, said protective base being an insulative member formed for seating on said stern closure surface and having an axis about which a rimlike portion surrounds an axially oriented hollow stack portion formed to protectively encompass said tubulation, said rimlike portion having a plurality of perforations spacedly arrayed therein to substantially match said connective lead arrangement and dimensioned to accommodate the protrusion of said leads therethrough, said improvement comprising: at least two of said perforations, substantially distally positioned from one another in said array, each being formed as a diverse-dimensioned retention perforation having a primary axis of symmetry therein and a first dimension greater than the diameter of the respective substantially round lead protruding therethrough and a second dimension smaller than the the diameter of said respective substantially round lead to provide spaced apart regions of pressured contact and regions of noncontact with said lead to effect a retention relationship between said base member and said respective connective lead; said regions of contact and noncontact having transition zones therebetween.

2. An improvement in a protective base for an electron tube according to claim 1 wherein said perforations other than said diverse-dimensioned retention perforations are formed as substantially circular perforations having diameters larger than the diameters of the respective rodlike lead members associated therewith, and wherein said first dimension of said retention perforations substantially equals the diameters of said substantially circular perforations.

3. An improvement in a protective base for an electron tube according to claim 1 wherein said lead arrangement and said perforations array are respectively disposed in a substantially circumferential manner in spaced relationship to said tube axis and said base axis, and wherein said diverse-dimensioned perforations are oriented with their primary axes of symmetry being substantially radially disposed in relationship to said base axis.

4. An improvement in a protective base for an electron tube according to claim 1 wherein at least one of said diversedimensioned perforations is formed as a substantially elongated opening having length and breadth dimensions corresponding to said first and said second dimensions respectively, said length dimension substantially coinciding with said primary axis of symmetry.

5. An improvement in a protective base for an electron tube according to claim 1 wherein at least one of said diversedimensioned perforations is formed as a substantially slotshaped opening defined by a pair of side and a pair of end portions, and wherein the bisectors of said sides and ends meet at a common point of intersection equidistant between the memtions, and wherein the bisectors of said sides meet at a common point of intersection equidistant between said sides, said second dimension of said retention perforation being defined through said point of intersection.

@7 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, Dat d March 9,

Invento Doyle Alfred Wood It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 71 of the specification "a" should read": Column 2, line 74 "a" should read-"a'"--.

Column 3, line 51 "0" should read--"o"'-- Column 3, line 61 "0" should read--"o"'--.

Column 3, line 62 "0" should read--"o"'--.

Signed and sealed this 3rd day of August 1971.

(SEAL) Attest:

.FLETGHER JR. WILLIAM E. SGHUYLER, ii i fiin g Officer Commissioner of Pate: 

1. An improvement in a protective base for an electron tube having a longitudinal axis therethrough and a plurality of substantially rigid substantially round rodlike connective leads arranged in spaced relationship to protrude from a substantially planar portion of the tube stem closure surface surrounding a sealed tubulation projecting substantially as axially therefrom, said protective base being an insulative member formed for seating on said stem closure surface and having an axis about which a rimlike portion surrounds an axially oriented hollow stack portion formed to protectively encompass said tubulation, said rimlike portion having a plurality of perforations spacedly arrayed therein to substantially match said connective lead arrangement and dimensioned to accommodate the protrusion of said leads therethrough, said improvement comprising: at least two of said perforations, substantially distally positioned from one another in said array, each being formed as a diverse-dimensioned retention perforation having a primary Axis of symmetry therein and a first dimension greater than the diameter of the respective substantially round lead protruding therethrough and a second dimension smaller than the the diameter of said respective substantially round lead to provide spaced apart regions of pressured contact and regions of noncontact with said lead to effect a retention relationship between said base member and said respective connective lead; said regions of contact and noncontact having transition zones therebetween.
 2. An improvement in a protective base for an electron tube according to claim 1 wherein said perforations other than said diverse-dimensioned retention perforations are formed as substantially circular perforations having diameters larger than the diameters of the respective rodlike lead members associated therewith, and wherein said first dimension of said retention perforations substantially equals the diameters of said substantially circular perforations.
 3. An improvement in a protective base for an electron tube according to claim 1 wherein said lead arrangement and said perforations array are respectively disposed in a substantially circumferential manner in spaced relationship to said tube axis and said base axis, and wherein said diverse-dimensioned perforations are oriented with their primary axes of symmetry being substantially radially disposed in relationship to said base axis.
 4. An improvement in a protective base for an electron tube according to claim 1 wherein at least one of said diverse-dimensioned perforations is formed as a substantially elongated opening having length and breadth dimensions corresponding to said first and said second dimensions respectively, said length dimension substantially coinciding with said primary axis of symmetry.
 5. An improvement in a protective base for an electron tube according to claim 1 wherein at least one of said diverse-dimensioned perforations is formed as a substantially slot-shaped opening defined by a pair of side and a pair of end portions, and wherein the bisectors of said sides and ends meet at a common point of intersection equidistant between the members of said pairs, said second dimension of said retention perforation being defined through said point of intersection.
 6. An improvement in a protective base for an electron tube according to claim 1 wherein at least one of said diverse-dimensioned perforations is formed as a substantially equilateral triangular shaped opening defined by three side portions, and wherein the bisectors of said sides meet at a common point of intersection equidistant between said sides, said second dimension of said retention perforation being defined through said point of intersection. 